Optical Coupling Structure

This U.S. non-provisional patent application claims priority under 35 U.S.C. § 119 of Korean Patent Application No. 10-2024-0077842, filed on Jun. 14, 2024, the entire contents of which are hereby incorporated by reference.

The present disclosure herein relates to an optical coupling structure, and more particularly, to an optical coupling structure including a light source containing a two-dimensional material and a planar optical waveguide.

In recent years, two-dimensional materials have attracted much attention due to their excellent optoelectronic properties and compatibility with various optical platforms. In particular, the van der Waals heterostructure, in which a single layer of heterogeneous two-dimensional materials are laminated, may operate as a light-emitting device by electrical or optical stimulation. The light source of the light-emitting device having the van der Waals heterostructure may also operate as a quantum light source. However, the design of optical structures for extracting light from the light-emitting device having the van der Waals heterostructure is not entirely satisfactory.

The present disclosure provides a light coupling structure that is capable of efficiently extracting light from a light-emitting device into an optical waveguide.

An embodiment of the inventive concept provides an optical coupling structure. In an embodiment, the optical coupling structure includes: an optical waveguide arranged in one direction; a light-emitting device provided on the optical waveguide to generate light; and a resonator provided below the light-emitting device and provided at one side of the optical waveguide to transmit the light to the optical waveguide.

In an embodiment, the resonator may include a disk resonator.

In an embodiment, the resonator may include a photonic crystal disk resonator.

In an embodiment, the resonator may include a photonic crystal ring resonator.

In an embodiment, the resonator may include a bar resonator.

In an embodiment, the optical waveguide may include: a first optical waveguide extending to one side of the resonator; and a second optical waveguide extending to the other side of the resonator.

In an embodiment, the resonator may include: external resonators provided outside both sides of the first optical waveguide and the second optical waveguide; and a central resonator provided between the first optical waveguide and the second optical waveguide and between the external resonators and smaller than each of the external resonators.

In an embodiment, the resonator may further include middle resonators provided between the external resonators and the central resonator and smaller than each of the external resonators and larger than the central resonator.

In an embodiment, the optical coupling structure may further include: a lower protective layer provided between the light-emitting device and the resonator and between the light-emitting device and the optical waveguide; and an upper protective layer provided on the light-emitting device.

In an embodiment, the optical coupling structure may further include a wave plate provided between the lower protective layer and the resonator.

In an embodiment of the inventive concept, an optical coupling structure includes: first and second optical waveguides arranged in one direction; a resonator provided at one side of the first and second optical waveguides or between the first and second optical waveguides; a lower protective layer provided on the first and second optical waveguides and the resonator; a light-emitting device comprising a lower metal oxide layer provided on the lower protective layer and an upper metal oxide layer provided on the lower metal oxide layer; and an upper protective layer provided on the light-emitting device.

In an embodiment, the resonator may include a disk resonator, a photonic crystal disk resonator, a photonic crystal ring resonator, or a bar resonator.

In an embodiment, the resonator may include: external resonators provided outside both sides of the first and second optical waveguides; middle resonators provided between the external resonators and smaller than each of the external resonators; and a central resonator provided between the middle resonators and smaller than each of the middle resonators.

In an embodiment, the middle resonators and the central resonator may be provided between the first and second optical waveguides.

In an embodiment, the optical coupling structure may further include a wave plate provided between the lower protective layer and the resonator.

Exemplary embodiments of technical ideas of the inventive concept will be described with reference to the accompanying drawings so as to sufficiently understand constitutions and effects of the inventive concept. The technical ideas of the inventive concept may, however, be embodied in different forms and should not be construed as limited to the embodiment set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the inventive concept to those skilled in the art. Further, the inventive concept is only defined by scopes of claims.

Like reference numerals refer to like elements throughout the specification. The embodiments in the detailed description will be described with exemplary block diagrams, perspective views, and/or cross-sectional views as ideal exemplary views of the inventive concept. In the figures, the dimensions of regions are exaggerated for effective description of the technical contents. Areas exemplified in the drawings have general properties and are used to illustrate a specific shape of a device. Thus, this should not be construed as limited to the scope of the inventive concept. Also, although various terms are used to describe various components in various embodiments of the inventive concept, the component are not limited to these terms. These terms are only used to distinguish one component from another component. The embodiments described and exemplified herein include complementary embodiments thereof.

In the following description, the technical terms are used only for explaining a specific exemplary embodiment while not limiting the inventive concept. In this specification, the terms of a singular form may comprise plural forms unless specifically mentioned. The meaning of ‘comprises’ and/or ‘comprising’ does not exclude other components besides a mentioned component.

Hereinafter, the present disclosure will be described in detail by explaining preferred embodiments of the technical ideas of the inventive concept with reference to the attached drawings.

are perspective views illustrating an example of an optical coupling structureaccording to an embodiment of the inventive concept.is a cross-sectional view of.

Referring to, an optical coupling structureaccording to an embodiment of the inventive concept may include a substrate, an optical waveguide, a resonator, and a light-emitting device.

The substratemay include silicon oxide (SiO). The substratemay include silicon, glass, or quartz, but an embodiment of the inventive concept is not limited thereto.

The optical waveguidemay be provided on the substrate. The optical waveguidemay be arranged in one direction. Alternatively, the optical waveguidemay extend in one direction. The optical waveguidemay have a refractive index greater than that of the substrate. For example, the optical waveguidemay include silicon (Si), silicon nitride (SiN), or silicon oxide. According to an embodiment, the optical waveguidemay include a first optical waveguideand a second optical waveguide. The first optical waveguidemay be provided on one side of the substrate. The second optical waveguidemay be provided on the other side of the substrate. The first optical waveguideand the second optical waveguidemay be aligned or arranged in one direction.

The resonatormay be provided at one side of the optical waveguide. The resonatormay be provided at one side between the first optical waveguideand the second optical waveguide. The resonatormay have the same thickness as the optical waveguide. For example, the resonatormay include a disk resonator. The resonatormay have a circular shape in a planar perspective and a square shape in a vertical perspective. The resonatormay be provided below the light-emitting device. The resonatormay extract lightfrom the light-emitting deviceto provide and/or transmit the light to the optical waveguide. The resonatormay have a refractive index that is the same as that of the optical waveguide. The resonatormay include silicon (Si), silicon nitride (SiN), or silicon oxide.

A clad layermay be provided on the substrateoutside the resonatorand the optical waveguide. The clad layermay have a refractive index that is the same as that of substrate. The clad layermay include silicon oxide.

A lower protective layermay be provided on the optical waveguide, the resonator, and the clad layer. The lower protective layermay be a lower diffusion barrier layer. The lower protective layermay include hexagonal boron nitride (hBN).

The light-emitting devicemay be provided on the lower protective layer. The light-emitting devicemay be provided on the resonatorand the optical waveguide. The light-emitting devicemay generate lightusing a bias voltage provided to electrodesconnected to both sides of the light-emitting device. For example, the light-emitting devicemay generate lighthaving a circular polarization component. Alternatively, the light-emitting devicemay generate lighthaving a linear polarization component, but this embodiment of the inventive concept is not limited thereto.

Referring to, when the light-emitting devicegenerates a right-handed circular polarization component, the resonatormay selectively transmit the lighthaving the right-handed circular polarization componentto the first optical waveguide. When the light-emitting devicegenerates a left-handed circular polarization component, the resonatormay selectively transmit the lighthaving the right-handed circular polarization componentto the second optical waveguide.

According to an embodiment, the light-emitting devicemay include a two-dimensional material. For example, the light-emitting devicemay have a van der Waals heterostructure. The light-emitting devicemay include a lower metal oxide layerand an upper metal oxide layer. The lower metal oxide layermay include at least one of MoS, WS, MoSe, or WSe. An upper metal oxide layermay be provided on the lower metal oxide layer. The upper metal oxide layermay include at least one of MoS, WS, MoSe, or WSe. Each of the lower metal oxide layerand the upper metal oxide layermay include a laminated structure of MoS/WSe, MoSe/WSe, or WSe/WS. One of the electrodesmay be connected to the lower metal oxide layer, and the other may be connected to the upper metal oxide layer.

Referring to, an upper protective layermay be provided on the upper metal oxide layer. The upper protective layermay be an upper diffusion barrier layer. The upper protective layermay include hexagonal boron nitride (hBN).

Therefore, the optical coupling structureaccording to an embodiment of the inventive concept may use the resonatorprovided at one side of the optical waveguidebelow the light-emitting deviceto efficiently extract or provide the lightof the light-emitting deviceto the optical waveguide.

are perspective views illustrating an example of the optical coupling structureaccording to an embodiment of the inventive concept.

Referring to, the resonatorshaving the optical coupling structureaccording to an embodiment of the inventive concept may be provided at both sides of the optical waveguide. The resonatorsmay be arranged in a direction that intersects the direction of the optical waveguide. When the optical waveguideis arranged in a first direction, the resonatorsmay be arranged in a second direction perpendicular to the first direction. The resonatorsmay transmit the lightto the first optical waveguideand the second optical waveguide. The wavelengths of the lighttransmitted to the first optical waveguideand the second optical waveguidemay be different or the same.

Referring to, the resonatorsmay transmit the lighthaving a right-handed circular polarization componentto the first optical waveguideand the second optical waveguide. The lightin the first optical waveguidemay have a first wavelength Δ. The lightin the second optical waveguidemay have a second wavelength λ. For example, the first wavelength Δand the second wavelengthmay be different from each other or may be the same.

Referring to, the resonatorsmay transmit the lighthaving the left-handed circular polarization componentto the first optical waveguideand the second optical waveguide. The lightin the first optical waveguidemay have a second wavelength. The lightin the second optical waveguidemay have a first wavelength Δ. The first wavelength Δand the second wavelengthmay be different from each other or may be the same.

The substrateand the light-emitting devicemay be configured the same as those in.

is a perspective view illustrating an example of the optical coupling structureaccording to an embodiment of the inventive concept.is a cross-sectional view of.

Referring to, the resonatorhaving the optical coupling structuremay include a photonic crystal disk resonator. According to an embodiment, the resonatormay have a plurality of edge holes. The edge holesmay be provided in an edge of the resonator. The edge holesmay be arranged circularly in a plan respective. The edge holesmay efficiently transmit the lighthaving the circular polarization component to the optical waveguide.

The substrate, the clad layer, the optical waveguide, the light-emitting device, the lower protective layer, and the upper protective layermay have the same configurations as those in.

illustrate an example of the resonatorof.illustrates an example of the resonatorof.illustrates an example of a general photonic crystal line resonator.

Referring to, each of resonatorssuch as a photonic crystal disk resonator and a disk resonator may have a circular shape in the planar respective. Among them, edge holesof the photonic crystal disk resonatormay have the same size, unlike the holes of the general photonic crystal line resonator illustrated in. The resonatormay have a defective area. The defective areamay be provided at one side of the edge of the resonator. The defective areamay deteriorate or improve transmission efficiency of light.

is a perspective view illustrating an example of the optical coupling structureaccording to an embodiment of the inventive concept.

Referring to, in the optical coupling structureaccording to an embodiment of the inventive concept, the plurality of resonatorsmay be provided at both sides of the optical waveguide. The plurality of resonatorsmay improve the transmission efficiency of the light.

The substrate, the optical waveguideand the light-emitting devicemay be configured to be the same as those in.

is a perspective view illustrating an example of the optical coupling structureaccording to an embodiment of the inventive concept.is a cross-sectional view of.

Referring to, the resonatorhaving the optical coupling structuremay include a photonic crystal ring resonator. According to an embodiment of the inventive concept, the resonatormay have a plurality of edge holesand a center hole.